Packaging container with tear-open thread

ABSTRACT

A container comprising a body and lid heat-sealed together by means of a thermoplastic resin coating. In order to open the container, the seal is broken by means of a tear-open thread placed inwardly of the sealing area, the ends of which thread emerge from the container traversing the seal and are impregnated with an oil, e.g. mineral, vegetable or animal oil, moistening the sealing layers, in order to prevent bacteria from infiltrating the inside of the container along the tear-open thread thus contaminating the contents of the container.

United States Patent [191 Bloeck PACKAGING CONTAINER WITH TEAR-OPEN THREAD [75] Inventor: Siegfried Bloeck, Kreuzlingen,

Switzerland [73] Assignee: Swiss Aluminum Ltd., Chippis,

' Switzerland 22 Filed: Nov. 14,1972

21 Appl. No.: 306,451.

[30] Foreign Application Priority Data Nov. 19, 1971 Switzerland 16842/71 [52] US. Cl 220/49, 229/51 S [51] Int. Cl B65d 17/20 [58] Field of Search 220/49; 229/51 S [56] References Cited UNITED STATES PATENTS 3,362,57] 7/1968 Kuhne 220/49 [451 Mar. 26, 1974 2/1970 Matthews 229/51 S 9/1959 Vanhoof 220/49 Primary Examiner-George T. Hall Attorney, Agent, or FirmErnest F. Marmorek [5 7 ABSTRACT A container comprising a body and lid heat-sealed together by means of a thermoplastic resin coating. in order to open the container, the seal is broken by means of a tear-open thread placed inwardly of the sealing area, the ends of which thread emerge from the container traversing the seal and are impregnated with an oil, e.g. mineral, vegetable or animal oil, moistening the sealing layers, in order to prevent bacteria from infiltrating the inside of the container along the tear-open thread thus contaminating the contents of the container. A

6 Claims, 3 Drawing Figures I PACKAGING CONTAINER WITH TEAR-OPEN THREAD This invention relates to heat-sealed containers, made from a synthetic resin or from aluminum foil coated with a synthetic resin, the seal being provided with a tear-open thread to facilitate the opening of the container.

It has now been found that the leading-out of the thread from the seal presents some difficulties, because the seal should be absolutely tight at the spot too where the thread leaves the seal, in order to prevent bacteria from infiltrating into the container along the thread, and deteriorating the contents.

The U.S. Pat. No. 3,362,571 describes such a con tainer with a tear-open thread, the latter being by preference threaded from single threads made from synthetic resin. As a rule these synthetic resin threads do not have a strong affinity to the layers of synthetic resins forming the coating of the lid and the body of the container and thus to the seal of the container; these coatings are normally high-density, polyethylene, polypropylene, polyamides, or copolymers of ethylene and vinylacetate. Therefore the possibility of an infiltration of bacteria along the thread cannot be excluded with absolute certainty and consequently the tightness against bacteria cannot be granted if the container and its contents are carefully examined.

The present invention will eliminate this uncertainty and bring-forth a better seal against bacteria.

The present invention relates to a container with a tear-open thread, comprising a body which receives the contents and has its upper rim bent outwardly to form the sealing flange, and a lid made from a foil which by means of a synthetic resin has its rim heat-sealed to the sealing flange of the body, and a threaded tear-open thread, the latter being positioned within the container and inwardly of the seal, and the ends of which thread are led out between the sealing flanges of the body and the lid. The improvement lies in the feature that the tear-open thread at least at its ends leading out of the container is impregnated with an oil which moistens the sealing layers.

The drawing shows as examples two embodiments of the invention:

FIG. 1 is a cross-sectional view of a container with tear open thread;

FIG. 2 is a top plan view of the same container; and

FIG. 3 is a fragmentary cross-sectional view showing a modified form of construction of the portion shown at A in FIG. 1.

A cup-shaped container body 1 manufactured by deep-drawing in the usual manner has at its upper rim portion a sealing flange 2. While the container is shown in the drawing with circular ground-plan, it may be of oval, angular, or of any other shape. A lid 3 of corresponding shape has a border flange 4 which is welded or heat-sealed to the sealing flange 2 by pressure and heat. The container body and lid may be'made from synthetic material, e. g. polyethylene, or from aluminum foil, or the bodymay be made from one and the lid from another material. The invention is especially advantageousfor containers, the body and lid of which are made from aluminum foilfln this case body and lid are heat-sealed in a well known manner by means of an intermediate layer of synthetic material. It is preferable to coat the container body and lid with polyethylene. When sealed by means of a heat-sealing device, the sealing and border flanges are pressed together, the coating melting within the reach of the sealing flange and resulting in a strong and tight seal.

The lid 3 has a depression 10 extending over the entire opening of the container body 1. Against a substantially vertical wall of this depression, facing the wall of the container body, the tear open thread 5 is placed.

It is beneficial to have the wall of the depression slightly inclined inwardly towards the center of the lid, see FIG. 3. Thereby the thread gets a better hold and is less liable to slip downward.

The depression of the lid serves advantageously to keep the container body dustproof, as the lid can be readily reset after being opened. For this purpose the rim of the container body has a corresponding ridge 6 as shown in FIG. 1.

In FIG. 3 the depression 10 is shaped with an additional bend 7 protruding above the border flange 4. When the container is opened the line of cutting follows this bend thus permitting an easier grip to remove the lid.

The two ends of the tear-open thread 5 are led out between the sealing flange 2 of the body and the border flange 4 of the lid. The sealing flange 2 is curved inwards at its edge as shown at 8, which serves merely to avoid a sharp edge of the flange and injuries caused thereby, but has nothing to do with the sealing of the container. At the spot where the thread is led out of the container the inwardly curved portion is cutout. The thread is applied after the curving in of the flange 2 and the ends are fixed by two points protruding into the cutout part of the curve which are, after application of the thread, pressed together.

At the one end of the thread there is a globule, a seal, or a pull tab 9 facilitating a better grip of the thread. After tearing open, the lid may be entirely removed if the ends of the thread are led out at the same place, or, it'may remain connected to the container body if the ends of the thread are led out apart as shown in FIG. 2. It is also possible to unite the two ends of the thread in the same pull tab. The impregnation of thread 5 may be obtained with mineral oils, e.g. paraffin oil, as well as vegetable or animal oils, e.g. olive oil. It has been found too that the thread 5 need not necessarily to be made from threaded synthetic resin thread; it may be a silk thread as well.

The tear'open thread 5 need not to be impregnated over its entire length. It is only important that it be impregnated at its ends'leading out of the container 11. The thread 5 may be impregnated, e.g. only within the reach of the sealing area. In this case, the sealing rim of the containerll may be moistened with the oil prior to the sealing operation at the spot where the ends of the thread 5 come out of the container 1 1; or there may be impregnated only the led-out ends of the thread 5 after the sealing.

The impregnated thread 5 may be laid in the depression '10 situated in the neighbourhood of the inner border of the sealing area, either in the lid or in the body or in the wall of a depressed portion of the lid facing the wall of the container body 1. One or both of the ends of the thread led out of the container 11 may be provided with a gripping tab.

EXAMPLES l. A threaded thread of Terylene (100 den) was im-' pregnated with paraffin oil and laid into an aluminum container coated with polypropylene and filled with a culture medium, in such a way that the ends of the thread were sticking out of the container. The container was then heat-sealed with an aluminum lid coated with polypropylene.

2. In a like container as in example 1, filled with herring in tomato sauce, a threaded silk thread was used, which was impregnated with a hydrogenated fish-body oil.

3. A test similar to that in example 1. However the thread was not previously impregnated over its entire length. Only at the lead-out spot a drop of olive oil was brought on the sealing flange prior to heat-sealing.

4. The ends of the thread were impregnated with paraffin oil only after sealing.

All the examples showed the containers absolutely tight when examined for bacteria. On the other hand in the containers without impregnation of the tear-open threads the contents were contaminated; that means that the containers were not absolutely tight.

What is claimed is:

1. In a container having a body for receiving filling goods, a rim in the body bent to form a sealing flange, a lid having a rim adapted for obtaining a seal with the sealing flange, and a threaded tear-open thread arranged inwardly of the seal and within the container, the ends of the thread being let out of the container between the sealing flange and the lid, the improvement comprising an oil for impregnating at least a portion of the thread to prevent bacteria infiltration into the container along the thread.

2. The container as claimed in claim 1, wherein the oil is a paraffin oil.

3. The container as claimed in claim 1, wherein the oil is a vegetable oil.

4. The container as claimed in claim 1, wherein the oil is an animal oil.

5. The container as claimed in claim 1, wherein the thread is impregnated with the oil only in the vicinity of the seal between the sealing flange and the lid.

6. The container as claimed in claim 1, wherein the thread is impregnated with the oil only beyond the seal between the sealing flange and the lid. 

1. In a container having a body for receiving filling goods, a rim in the body bent to form a sealing flange, a lid having a rim adapted for obtaining a seal with the sealing flange, and a threaded tear-open thread arranged inwardly of the seal and within the container, the ends of the thread being let out of the container between the sealing flange and the lid, the improvement comprising an oil for impregnating at least a portion of the thread to prevent bacteria infiltration into the container along the thread.
 2. The container as claimed in claim 1, wherein the oil is a paraffin oil.
 3. The container as claimed in claim 1, wherein the oil is a vegetable oil.
 4. The container as claimed in claim 1, wherein the oil is an animal oil.
 5. The container as claimed in claim 1, wherein the thread is impregnated with the oil only in the vicinity of the seal between the sealing flange and the lid.
 6. The container as claimed in claim 1, wherein the thread is impregnated with the oil only beyond the seal between the sealing flange and the lid. 